1. Field of the Invention
The present invention relates to a semiconductor light emitting device and a method of manufacturing the same.
2. Description of the Related Art
A light emitting diode (LED) is a semiconductor device able to emit light of various colors due to electron-hole recombination occurring at a p-n junction between p-type and n-type semiconductors when current is applied thereto. Such an LED is advantageous over a filament-based light emitting device in that it has a long lifespan, low power consumption, superior initial-operation characteristics, and the like. These factors have continually boosted the demand for LEDs. Notably of late, a great deal of attention has been drawn to group III nitride semiconductors that can emit light in a blue/short wavelength region.
Since the development of nitride semiconductor devices, technical advances to broaden the range of applications thereof have been made. Thus, many studies are being conducted into determining how to utilize nitride semiconductor devices in general lighting apparatuses and electrical lighting sources. According to the related art, nitride light emitting devices have been used as components employed in low-current, low output mobile products. However, of late, the range of applications of nitride light emitting devices has been broadened to encompass the field of high-current, high-output products.
Meanwhile, a semiconductor layer constituting the LED has a high refractive index as compared with external air, an encapsulated material, or a substrate, reducing a critical angle determining an incident angle range in which light can be emitted. As a result, a considerable amount of light generated from an active layer is totally internally reflected to be emitted in a substantially undesired direction or be lost in a total internal reflection process, whereby light extraction efficiency may be reduced. Accordingly, a method of increasing an amount of light emitted in a desired direction and improving substantial luminance is required.